Britain will vote on whether to leave the European Union in a national referendum on June 23 that could have profound implications for the U.S., NBC News reported.
Here's what you need to know.
Why Does It matter to the U.S.?
The United States advocates a strong, stable Europe. Even a smooth "Brexit" would see Washington building a new relationship with both Britain and a Britain-free remainder of the EU. However, some observers fear the rump EU could begin to unravel, weakening America's allies and bringing instability.
Despite a weakened "special relationship" between Washington and London, Britain remains America's primary transatlantic military ally and its role in Europe is strategically important to the U.S.
Some predict a domino effect as other EU members consider their own departures, while other members fear that an EU without Britain would be economically dominated by Germany. Another structural crisis is the last thing Europe needs amid the biggest refugee crisis since World War Two, intractable economic woes and a nebulous security threat from international terrorism.